An anonymous anti-Muslim letter addressed "to the Children of Satan" and supporting President-elect Donald Trump was sent to Islamic centers in Georgia and California, a Muslim advocacy group said.

The letter, received by three centers in California and most-recently in Savannah, Ga., recalled the Jewish genocide of World War II, saying Trump is "going to do to you Muslims what Hitler did to the Jews."

The Council on American-Islamic Relations, the country's largest Muslim civil liberties group, condemned the letter and on Monday announced a visit to Savannah and an effort for interfaith outreach, as the group noted an uptick in hate crimes since 2015 and a similar jump after the Nov. 9 election of Trump.

"Although anti-Muslim bigotry has surged since Election Day, our community fears God, not anonymous hate mail,"said Edward Ahmed Mitchell, executive director of the Georgia chapter of CAIR. "Whoever sent these letters should know that they have only strengthened our resolve to keep practicing our faith, defending our rights and building bridges with our neighbors."